1badd7

Ok so I started modifying my '04 Navigator and really need to do a 2 1/2" manifold back exhaust removing the 4 factory cats and going down to 2 high flow cats. I've done this before on another Navigator I had but it wound up being waaay too loud so I would like to know what would give me the nicest throaty sound without that ear peircing sound at wot. Check out the following set ups and give me some advice, keep in mind that I have the 32 valve 5.4 motor and I will be removing 2 cats using flowmaster muffler(s) all work will be custom mandrel bent 2 1/2".

set up 1: no X pipe into one 2 in 2 out muffler

set up 2: X pipe into one 2 in 2 out muffler

set up 3: X pipe into 2 single in single out mufflers

all systems will end into 12" or longer resonated tips, use 2 high flow cats and exit where the factory exhaust does. Thanks in advance for all your help.

Hurstmeister

+1 for no x-pipe.

Hurst

GNs-r-slow

X pipe is useless if you're not running true duals

1badd7

I tought that an X pipe would help "balance" the exhaust and help keep it quiter and keep that raspy note down that 4 valves are known for.

Hurstmeister

Completely opposite.

X-pipe will promote and amplify raspiness in any and all V8's that an X-pipe is used on.

This is purely my opinion and based on nothing more than my own personal experience with 3 off road x-pipes on two 4.6 Mustangs (A 2v and a 4v) and on an LT1 Camaro. At idle they sound ok,.. but as the RPM's climb with an X-pipe so too does the exhaust note and tone creating what I like to describe as marbles bouncing around in a tin can. With the popping and raspiness that almost resembles an Indy V8 tone. Its a love it or hate it tone. Many guys absolutely love an X-pipe. I personally do not.

I experimented with several configurations.

4.6 with stock exhaust manifolds, off road x-pipe and chambered mufflers with pipes out the back was the worst. Loudest and produced the worst popping. Shaun at All American ended up with that x-pipe.

Replace the cast manifolds with long tube headers, off road x-pipe and chambered mufflers and tails,.. toned down the raspiness and hissing noise,. but the popping and marble sound was still there at high rpm's.

Replaced chambered mufflers with Dynomax bullet style spiral chamber mufflers got rid of the popping and marble sound,.. but completely changed the tone of the exhaust and made it unbearably loud. Guy in Texas now has this X-pipe.

Replaced the X-pipe with an H-pipe. Put the chambered mufflers back on. Now had a nice deep idle and aggressive tone through out the rshared_pm range,.. not too loud at low to mid rpm's,.. but did get loud at high rpm's. This combo produced what I like to refer to as the 'traditional' Flowmaster Mustang sound.

Again,.. all of this is purely opinionated. Yours and many others will have their own opinion of what sounds good.

The purpose of an H and X pipe are tuned to blend the pulses of odd fire engines. V6 is an even fire engine and why mid pipes with cross overs have no effect. V8 is an odd fire engine and can take advantage of pulse modulation through tuning the collector length on the headers and using a cross over pipe within the mid pipe. This only remains in effect if you continue the same exhaust through out the run from start to finish. If you go from a larger size pipe and at any point you reduce the diameter of the pipe,.. the entire exhaust is reduced to the smallest point of the exhaust. If you take an X or H pipe meant for a dual exhaust,.. and you Y it down into a single pipe,.. you've effectively canceled out any effectiveness of having a cross over pipe.

Hurst

1badd7

Thank you for your help, I know freeing up the exhaust helps with power and fuel efficiency and I just wanted a deeper note from the exhaust I just didn't want it to sound like a racecar like my first Navi did, I guess I need to investigate into a good muffler that flows well

1badd7

Thank you for your help, I know freeing up the exhaust helps with power and fuel efficiency and I just wanted a deeper note from the exhaust I just didn't want it to sound like a racecar like my first Navi did, I guess I need to investigate into a good muffler that flows well and isn't overly loud.